Huawei H12-831_V1.0 Exam With Confidence Using Practice Dumps

Comprehensive and Detailed In-Depth Explanation:

To determine the correct configuration, we need to analyze how MPLS LDP (Label Distribution Protocol) is correctly enabled on a Huawei router.

1. Required Steps to Enable MPLS LDP on R1

To enable MPLS LDP on R1 and establish LDP sessions, the following steps must be followed:

✅ Step 1: Configure the MPLS LSR ID (Loopback IP recommended)

MPLS LSR ID is a unique identifier for the Label Switch Router (LSR).

Command:

shell

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mpls lsr-id 1.1.1.1

Why?

The LSR ID must be configured for LDP to function properly in an MPLS network.

It is usually set to a loopback address for stability and consistency.

✅ Step 2: Enable MPLS Globally

Command:

shell

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mpls

Why?

This enables MPLS forwarding on the device.

✅ Step 3: Enable MPLS LDP Globally

Command:

shell

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mpls ldp

Why?

LDP is needed for label distribution in the MPLS domain.

Without this, routers cannot exchange MPLS labels.

✅ Step 4: Enable MPLS and LDP on the Required Interface

Command:

shell

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interface gigabitethernet 0/0/1

mpls

mpls ldp

Why?

MPLS must be enabled on interfaces that participate in MPLS forwarding.

LDP must also be enabled on these interfaces to distribute labels over MPLS links.

2. Analyzing the Answer Choices

✅ Option B (Correct)

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[R1] mpls lsr-id 1.1.1.1 ✅ (Sets LSR ID)

[R1] mpls ✅ (Enables MPLS globally)

[R1-mpls] quit

[R1] mpls ldp ✅ (Enables LDP globally)

[R1-mpls-ldp] quit

[R1] interface gigabitethernet 0/0/1

[R1-GigabitEthernet0/0/1] mpls ✅ (Enables MPLS on interface)

[R1-GigabitEthernet0/0/1] mpls ldp ✅ (Enables LDP on interface)

[R1-GigabitEthernet0/0/1] quit

This configuration correctly enables MPLS LDP on R1.

All required steps are followed, including the LSR ID, MPLS, LDP, and interface activation.

❌ Option A (Incorrect)

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[R1] mpls lsr-id 1.1.1.1

[R1] mpls

[R1-mpls] quit

[R1] mpls ldp

[R1-mpls-ldp] quit

[R1] interface gigabitethernet 0/0/1

[R1-GigabitEthernet0/0/1] mpls ✅

[R1-GigabitEthernet0/0/1] quit ❌ (Missing "mpls ldp" under interface)

Missing mpls ldp under interface configuration.

Without this, the interface will not establish an LDP session → Incorrect.

❌ Option C (Incorrect)

shell

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[R1] mpls

[R1-mpls] quit

[R1] mpls ldp

[R1-mpls-ldp] quit

[R1] interface gigabitethernet 0/0/1

[R1-GigabitEthernet0/0/1] mpls

[R1-GigabitEthernet0/0/1] mpls ldp

[R1-GigabitEthernet0/0/1] quit

Missing mpls lsr-id 1.1.1.1.

LSR ID is critical for LDP sessions → Incorrect.

❌ Option D (Incorrect)

shell

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[R1] mpls lsr-id 1.1.1.1

[R1] mpls

[R1-mpls] quit

[R1] interface gigabitethernet 0/0/1

[R1-GigabitEthernet0/0/1] mpls

[R1-GigabitEthernet0/0/1] mpls ldp

[R1-GigabitEthernet0/0/1] quit

Missing global MPLS LDP configuration (mpls ldp).

Without enabling LDP globally, labels will not be distributed.

This makes LDP sessions fail. → Incorrect.

Comprehensive and Detailed In-Depth Explanation:

To verify the correct answer, we need to analyze Bidirectional Forwarding Detection (BFD) behavior and the provided configuration.

1. Understanding BFD Configuration Parameters

BFD (Bidirectional Forwarding Detection) is a protocol used for fast failure detection between directly connected devices.

Key Configuration Parameters in BFD:

Peer IP (bind peer-ip)

This specifies the destination router’s IP address for the BFD session.

✅ Correctly configured on both R1 and R2.

Discriminator Local/Remote (discriminator local X / remote Y)

These values must match between the two routers.

✅ Correctly configured (R1: local 1, remote 2; R2: local 2, remote 1).

Min-TX Interval (min-tx-interval)

Defines the minimum transmit interval for BFD packets.

❌ Missing from R2’s configuration (could be a cause for mismatch).

Min-RX Interval (min-rx-interval)

Defines the minimum receive interval for BFD packets.

❌ Missing from R2’s configuration (could be a cause for mismatch).

2. Analyzing the Configuration on R1 and R2

✅ Configuration on R1 (Correct)

shell

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bfd tor2 bind peer-ip 10.0.12.2

discriminator local 1

discriminator remote 2

min-tx-interval 1500

min-rx-interval 1500

This configuration is correct.

❌ Configuration on R2 (Incomplete)

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bfd tor1 bind peer-ip 10.0.12.1

discriminator local 2

discriminator remote 1

Missing min-tx-interval and min-rx-interval.

3. Why the Answer is FALSE?

A BFD session does NOT go down due to mismatched timing parameters.

BFD dynamically negotiates timing values, meaning even if R2 is missing min-tx/min-rx values, the session should still establish.

However, the session will fail if the peer IP or discriminator values are incorrect (which they are NOT in this case).

The actual cause of failure in this case is likely the missing min-tx and min-rx settings on R2, NOT a mismatch between R1 and R2.